The Initial Response to Inhaled Nitric Oxide Treatment for Intensive Care Unit Patients with Acute Respiratory Distress Syndrome

Abstract

Background: Inhaled nitric oxide (INO) can improve hypoxemia and reduce pulmonary hypertension, but there is a wide range of response to INO. Objectives: The aim of this study was to evaluate the effect of different INO concentrations in acute respiratory distress syndrome (ARDS) patients. Methods: Thirty-two adult ARDS patients who were supported by mechanical ventilator were included. INO was given at a concentration of 1, 5, 10, 20 and 40 ppm, sequentially. Arterial blood gas and mean pulmonary artery pressure (MPAP) were measured 30 min after INO concentrations changed. Results: There was a significant increase in PaO₂/FiO₂ (p < 0.0001) and a decrease in pulmonary vascular resistance index and MPAP (p < 0.0001) after INO use. INO concentrations required for improving oxygenation were in the range of 1–20 ppm, whereas concentrations required for decreasing MPAP were in the range of 1–40 ppm. PaO₂/FiO₂ worsened when the INO dose was adjusted above 20 ppm. Sixty-nine percent of ARDS patients were responders; 31% of them were nonresponders. Among responders, 64% of patients responded at 1 ppm, 36% at 5 ppm. Conclusions: The optimal doses for improving oxygenation and reducing PAP differ. The maximum PaO₂/FiO₂ was observed at a lower INO concentration than that required for the minimal MPAP. There was no further improvement in PaO₂/FiO₂ when the INO dose was adjusted above 20 ppm. Higher doses of INO treatment worsened oxygenation.

The RIFLE Score Increases the Accuracy of Outcome Prediction in Patients with Acute Respiratory Distress Syndrome Undergoing Open Lung Biopsy

“…Respiratory failure with a high AaDO 2 level is a sign of tissue hypoxia. In such severely ill ARDS patients, tissue hypoxia is the primary cause of circulatory dysfunction, hypoxemia of the brain with unconsciousness, renal tubular necrosis in the kidneys, multiorgan failure and death [26, 27, 32]. …”

Early Short-Term Application of High-Frequency Percussive Ventilation Improves Gas Exchange in Hypoxemic Patients

“…These patients frequently do not respond to standard ventilatory techniques and, thus, high levels of oxygen, high positive end-expiratory pressure (PEEP), and complementary and intermittent techniques such as prone positioning, recruitment maneuvers, and nitric oxide have been used in an attempt to maintain or increase oxygenation [1,2,3,4]. Presently, the comparison between the clinical effectiveness of conventional ventilation (CV) and other techniques is warranted almost solely by gas exchange analysis, mortality, and ventilator-free days; commonly, patients are defined as responders if their baseline Pa o 2 /Fi o 2 increases by 10–20% [5,6].…”

Successful treatment of acute respiratory distress syndrome after hysterectomy for life-threatening atonic bleeding by inhaled nitric oxide

“…It has been suggested that iNO selectively relaxes vessels at the well-ventilated regions of the lung and that this results in improving the ventilation-perfusion mismatch and, therefore, improved oxygenation in ARDS patients [8]. In our case, iNO was considered to have redistributed pulmonary blood from the poorly ventilated regions to the well-ventilated regions.…”

“…The optimal dose of iNO to achieve the maximum effect in terms of improving oxygenation has been reported to vary from 1 to 20 ppm [8,[10][11][12], while high doses of iNO of [10 ppm [11,12] or [20 ppm [8] have also been shown to worsen oxygenation. One theory for this latter result is that a high dose of iNO can enter the poorly ventilated area, causing vasodilation of this area, possibly reducing the improvement in the ventilation-perfusion mismatch [8]. We started to administer iNO at 10 ppm to determine the patient's initial response to iNO and observed that iNO dramatically improved oxygenation without any adverse effects.…”

“…Some studies have demonstrated that the response to iNO is associated with an etiology of ARDS. In two studies, ARDS patients without septic shock had a higher response rate to iNO than those with septic shock [8,16]. It has been also suggested that nonsepsis-induced ARDS, such as ARDS after trauma, tends to be more sensitive to iNO than sepsis-induced ARDS [8], although the involved mechanisms still need to be elucidated.…”